Intravascular catheter shaft

ABSTRACT

A catheter shaft includes a polyoxymethylene-polyurethane elongate shaft including a proximal portion having about 80 to about 95 weight % polyoxymethylene and about 5 to about 20 weight % polyurethane, an intermediate portion having about 20 to about 50 weight % polyoxymethylene and about 50 to about 80 weight % polyurethane, and a distal portion having about 5 to about 20 weight % polyoxymethylene and about 80 to about 95 weight % polyurethane. The intermediate portion is disposed between the proximal portion and the distal portion.

RELATED APPLICATION

[0001] This application claims the benefit of priority under 35 U.S.C §119(e) to U.S. Provisional Application Serial No. 60/361,229, filed Feb.28, 2002, which is herein incorporated by reference.

FIELD OF THE INVENTION

[0002] The present invention generally relates to intravascular cathetershafts. More specifically, the present invention relates tointravascular catheter shafts for guide catheters, diagnostic catheters,balloon catheters, and the like.

BACKGROUND OF THE INVENTION

[0003] Diagnostic catheters and guide catheters are commonly used tofacilitate the diagnosis and treatment of vascular diseases such ascoronary artery disease and peripheral vascular disease. Ballooncatheters are commonly used to treat vascular disease by dilatingstenotic lesions. Because such intravascular catheters must be navigatedto remote vascular sites through vascular anatomy that may be verytortuous, it is desirable to have a catheter shaft that exhibitsimproved torqueability, trackability and pushability.

SUMMARY OF THE INVENTION

[0004] The invention provides several alternative designs, materials andmethods of manufacturing alternative catheter structures and assemblies.

[0005] One embodiment includes a catheter shaft having apolyoxymethylene-polyurethane elongate shaft including a proximalportion having about 80 to about 95 weight % polyoxymethylene and about5 to about 20 weight % polyurethane, an intermediate portion havingabout 20 to about 50 weight % polyoxymethylene and about 50 to about 80weight % polyurethane, and a distal portion having about 5 to about 20weight % polyoxymethylene and about 80 to about 95 weight %polyurethane. In one alternative embodiment, the distal portion hasabout 0 to about 5 weight % polyoxymethylene and about 95 to about 100weight % polyurethane. The intermediate portion is disposed between theproximal portion and the distal portion.

[0006] A further embodiment includes a catheter shaft having apolyoxymethylene-polyurethane elongate shaft including a proximalportion having a flexural modulus of about 380 to about 210 ksi, anintermediate portion having a flexural modulus of about 30 to about 90ksi, and a distal portion having a flexural modulus of less than about30 ksi. The intermediate portion is disposed between the proximalportion and the distal portion.

[0007] A further embodiment includes a catheter having an inner tubularmember having a proximal end, a distal end and a longitudinal surface. Asupport member is disposed over a substantial portion of thelongitudinal surface. The support member has a distal end terminatedproximal of the inner tubular member distal end. Apolyoxymethylene-polyurethane elongate shaft is disposed over the innertubular member. The polyoxymethylene-polyurethane elongate shaftincludes a proximal portion having about 80 to about 95 weight %polyoxymethylene and about 5 to about 20 weight % polyurethane, anintermediate portion having about 20 to about 50 weight %polyoxymethylene and about 50 to about 80 weight % polyurethane, and adistal portion having about 5 to about 20 weight % polyoxymethylene andabout 80 to about 95 weight % polyurethane. In one alternativeembodiment, the distal portion has about 0 to about 5 weight %polyoxymethylene and about 95 to about 100 weight % polyurethane. Theintermediate portion is disposed between the proximal portion and thedistal portion.

[0008] A further embodiment includes a balloon catheter having an innertubular member having a proximal end, a distal end and a longitudinalsurface. A support member is disposed over a substantial portion of thelongitudinal surface. The support member has a distal end terminatedproximal of the inner tubular member distal end. Apolyoxymethylene-polyurethane elongate shaft includes a proximal portionhaving about 80 to about 95 weight % polyoxymethylene and about 5 toabout 20 weight % polyurethane, an intermediate portion having about 20to about 50 weight % polyoxymethylene and about 50 to about 80 weight %polyurethane, and a distal portion having about 5 to about 20 weight %polyoxymethylene and about 80 to about 95 weight % polyurethane. In onealternative embodiment, the distal portion has about 0 to about 5 weight% polyoxymethylene and about 95 to about 100 weight % polyurethane. Theintermediate portion is disposed between the proximal portion and thedistal portion. A balloon is disposed about the distal portion of thepolyoxymethylene-polyurethane elongate shaft.

[0009] The above summary of some embodiments is not intended to describeeach disclosed embodiment or every implementation of the presentinvention. The Figures, and Detailed Description which follow moreparticularly exemplify these embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The invention may be more completely understood in considerationof the following detailed description of various embodiments of theinvention in connection with the accompanying drawings in which:

[0011]FIG. 1 is a plan view of an intravascular catheter in accordancewith an embodiment of the present invention shown as a guide ordiagnostic catheter;

[0012]FIG. 2 is a cross-sectional view taken along line 2-2 in FIG. 1;

[0013]FIG. 3 is a longitudinal sectional view taken along line 3-3 inFIG. 1;

[0014]FIG. 4 is a plan view of an intravascular catheter in accordancewith another embodiment of the present invention shown as a ballooncatheter; and

[0015]FIG. 5 is a cross-sectional view taken along line 5-5 in FIG. 4.

[0016] While the invention is amenable to various modifications andalternative forms, specifics thereof have been shown by way of examplein the drawings and will be described in detail. It should beunderstood, however, that the intention is not to limit the invention tothe particular embodiments described. On the contrary, the intention isto cover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0017] For the following defined terms, these definitions shall beapplied, unless a different definition is given in the claims orelsewhere in this specification.

[0018] All numeric values are herein assumed to be modified by the term“about,” whether or not explicitly indicated. The term “about” generallyrefers to a range of numbers that one of skill in the art would considerequivalent to the recited value (i.e., having the same function orresult). In many instances, the terms “about” may include numbers thatare rounded to the nearest significant figure.

[0019] Weight percent, percent by weight, wt %, wt-%, % by weight, andthe like are synonyms that refer to the concentration of a substance asthe weight of that substance divided by the weight of the compositionand multiplied by 100.

[0020] The recitation of numerical ranges by endpoints includes allnumbers within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3,3.80, 4, and 5).

[0021] As used in this specification and the appended claims, thesingular forms “a”, “an”, and “the” include plural referents unless thecontent clearly dictates otherwise. As used in this specification andthe appended claims, the term “or” is generally employed in its senseincluding “and/or” unless the content clearly dictates otherwise.

[0022] The following detailed description should be read with referenceto the drawings in which similar elements in different drawings arenumbered the same. The drawings, which are not necessarily to scale,depict illustrative embodiments and are not intended to limit the scopeof the invention.

[0023] Refer now to FIG. 1 which illustrates an intravascular catheterin accordance with an embodiment of the present invention. For purposesof illustration and discussion only, the intravascular catheter shown inFIG. 1 is in the form of a guide or diagnostic catheter 10, but maycomprise virtually any catheter used for intravascular applications. Forexample, the intravascular catheter may comprise a balloon catheter 40as discussed with reference to FIG. 4.

[0024] The guide or diagnostic catheter 10 may have a length and anoutside diameter sufficient to enable intravascular insertion andnavigation. For example, the catheter 10 may have a length ofapproximately 100 cm to 150 cm and an outside diameter of approximately4 to 9 French. Guide or diagnostic catheter 10 may be substantiallyconventional except as described herein and shown in the drawings.

[0025] The catheter 10 includes an elongate shaft 12 having a proximalportion 17, a distal portion 19 and an intermediate portion 15 disposedbetween the proximal portion 17 and the distal portion 19. A distal tip16 is connected to the distal end of the elongate shaft 12. The distaltip 16, the distal portion 19 and the intermediate portion 15 of theelongate shaft 12 may be curved depending on the particular clinicalapplication. The elongate shaft 12 and the distal tip 16 include a lumen18 (shown in FIG. 4) extending therethrough to facilitate insertion ofother medical devices (e.g., guide wires, balloon catheters, etc.)therethrough, and/or to facilitate injection of fluids (e.g., radiopaquedye, saline, drugs, etc.) therethrough. A manifold 14 can be connectedto the proximal end of the proximal portion 17 of the elongate shaft 12to facilitate connection to other medical devices (e.g., syringe,Y-adapter, etc.) and to provide access to the lumen 18.

[0026] The proximal portion 17 of the elongate shaft 12 may be fromabout 60 to about 135 cm or about 60 to about 90% of the total length.The intermediate portion 15 of the elongate shaft 12 may be from about15 to about 30 cm or about 15 to about 20% of the total length. Thedistal portion 19 of the elongate shaft 12 may be from about 2 to about10 cm or about 2 to about 7% of the total length.

[0027] The elongate shaft 12 can be formed from a polymer blend ofpolyoxymethylene and polyurethane hereinafter denoted as“polyoxymethylene-polyurethane”. The proximal portion 17, intermediateportion 15 and distal portion 19 are each formed with a varying amountof polyoxymethylene. The proximal portion 17 can have about 80 to about95 weight % polyoxymethylene. The intermediate portion 15 can have about20 to about 50 weight % polyoxymethylene. The distal portion 19 can haveabout 5 to about 20 weight % polyoxymethylene. In an alternativeembodiment, the distal portion can include about 0 to about 5 weight %polyoxymethylene.

[0028] The proximal portion 17, intermediate portion 15 and distalportion 19 are each formed with a varying amount of polyurethane. Theproximal portion 17 can have about 5 to about 20 weight % polyurethane.The intermediate portion 15 can have about 50 to about 80 weight %polyurethane. The distal portion 19 can have about 80 to about 95 weight% polyurethane. In one alternative embodiment, the distal portion caninclude about 95 to about 100 weight % polyurethane.

[0029] The proximal portion 17, intermediate portion 15 and distalportion 19 are each formed with varying flexural modulus. The proximalportion 17 can have a flexural modulus of about 210 to about 380 ksi.The intermediate portion 15 can have a flexural modulus of about 30 toabout 90 ksi. The distal portion 19 can have a flexural modulus of lessthan about 30 ksi or from about 1 to about 30 ksi or from about 15 toabout 30 ksi.

[0030] As best seen in FIGS. 2 and 3, the elongate shaft 12 may bemulti-layered (shown) or uni-layered (not shown). In the multi-layerembodiment (shown), the elongate shaft 12 may include apolyoxymethylene-polyurethane outer layer 30, a reinforcement layer 32and an inner layer 34. In the uni-layer embodiment (not shown), theelongate shaft 12 may comprise a single polyoxymethylene-polyurethanelayer 30. The distal tip 16 may comprise the outer layer 30 extendingbeyond the inner layer 34 and the reinforcement layer 32 to define asoft atraumatic tip.

[0031] The inner layer 34 may comprise a lubricious polymer such ashigh-density polyethylene (HDPE) or polytetrafluoroethylene (PTFE), forexample. Alternatively, the inner layer 34 may comprise apolyoxymethylene homopolymer or a polyoxymethylene blend as discussedherein with reference to the outer layer 30. The reinforcement layer 32may comprise a braided metallic wire or coil, for example.

[0032] The outer layer 30 may be formed, for example, by extrusion of apolyoxymethylene pre-blend or by co-extrusion of the polyoxymethylenewith the polyurethane such as by interrupted layer co-extrusion (ILC).Alternatively, the outer layer 30 may be formed of separated extrudedtubular segments subsequently fused together. A suitablepolyoxymethylene is commercially available under the trade name Delrin™commercially available from DuPont Wilmington, Del.

[0033]FIG. 4 illustrates an intravascular catheter in accordance withanother embodiment of the present invention. For purposes ofillustration and discussion only, the intravascular catheter shown inFIG. 4 is in the form of an intravascular balloon catheter 40. Theballoon catheter 40 may be substantially conventional except asdescribed herein and shown in the drawings.

[0034] The balloon catheter 40 includes an elongate shaft 42 having aproximal portion 41, a distal portion 45 and an intermediate portion 43disposed between the proximal portion 41 and the distal portion 45. Aninflatable balloon 46 is connected to the distal portion 45 of theelongate shaft 42. Depending on the type (over-the-wire, fixed-wire,single-operator-exchange, etc.) of balloon catheter 40, all or a portionof the elongate shaft 42 may include an inner tube 44 defining a guidewire lumen 52 therein, and an outer tube 46 disposed thereon to definean annular inflation lumen 54 therebetween. A manifold 44 can beconnected to the proximal end of the proximal portion 41 of the elongateshaft 42 to facilitate connection to other medical devices (e.g.,syringe, Y-adapter, etc.) and to provide access to the lumen 18.

[0035] The inner tube 44 may comprise a lubricious polymer such as HDPEor PTFE, for example. The outer tube 46 may comprise a polymer blendthat is similar to or the same as the polymer blends of the outer layer30 discussed with reference to FIG. 1. In addition, the manufacture andarrangement of parts for outer tube 46 may be similar to or the same asthat discussed with reference to the outer layer 30.

EXAMPLES

[0036] The following polyoxymethylene blend material test data isprovided by way of example, not limitation: Sample No. Composition 1100% Polyoxymethylene—Delrin 150SA 2  20% Urethane  80% Polyoxymethylene3  40% Urethane  60% Polyoxymethylene 4  50% Urethane  50%Polyoxymethylene 5  60% Urethane  40% Polyoxymethylene

[0037] Test Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Tensile St at9830 7020 5170 4360 3090 Yield (psi) Elongation at 19 27 42 50 150 Yield(%) Tensile St at 9670 5660 5270 4600 7260 Break (psi) Elongation at 37100 400 330 480 Break (%) Tensile Set 6 49 310 240 310 at Break (%)Tensile 412600 237600 149400 115800 30530 Modulus (psi) Flexural 397200218100 117800 92670 46930 Modulus (psi) Shore D 80 75 65 58 50 Hardness(points) Vicat 173.7 171.9 166.2 150.8 134.3 Softening Point (° C.) DSDMelt 189 189.8 188.6 183.8 183.7 Point (° C.) Melt Index 10.9 8.7 8 6.46.2

[0038] The polyoxymethylene-polyurethane blends of the present inventionhave been found to provide catheter shafts with enhanced stiffness, kinkresistance, and curve performance. For example, kink test resultsindicate that catheter tubes formed of polyoxymethylene-polyurethaneblends are more kink resistant than the prior art.

[0039] The present invention should not be considered limited to theparticular examples described above, but rather should be understood tocover all aspects of the invention as fairly set out in the attachedclaims. Various modifications, equivalent processes, as well as numerousstructures to which the present invention may be applicable will bereadily apparent to those of skill in the art to which the presentinvention is directed upon review of the instant specification. Itshould be understood that this disclosure is, in many respects, onlyillustrative. Changes may be made in details, particularly in matters ofshape, size, and arrangement of steps without exceeding the scope of theinvention. The scope of the invention is, of course, defined in thelanguage in which the appended claims are expressed.

What is claimed is:
 1. A catheter shaft comprising: apolyoxymethylene-polyurethane elongate shaft including a proximalportion having about 80 to about 95 weight % polyoxymethylene and about5 to about 20 weight % polyurethane, an intermediate portion havingabout 20 to about 50 weight % polyoxymethylene and about 50 to about 80weight % polyurethane, and a distal portion having about 5 to about 20weight % polyoxymethylene and about 80 to about 95 weight %polyurethane, wherein the intermediate portion is disposed between theproximal portion and the distal portion.
 2. The catheter shaft accordingto claim 1, further comprising an inner polytetrafluoroethylene tubularmember disposed within the polyoxymethylene-polyurethane elongate shaft.3. The catheter shaft according to claim 2, further comprising a braidedmetallic support member disposed between the innerpolytetrafluoroethylene tubular member and thepolyoxymethylene-polyurethane elongate shaft.
 4. The catheter shaftaccording to claim 1, wherein the proximal portion, intermediate portionand distal portion define a total shaft length and the proximal portionis about 60 to about 90% of the total length, the intermediate portionis about 15 to about 20% of the total length, and the distal portion isabout 2 to about 7% of the total length.
 5. A catheter shaft comprising:a polyoxymethylene-polyurethane elongate shaft including a proximalportion having a flexural modulus of about 380 to about 210 ksi, anintermediate portion having a flexural modulus of about 30 to about 90ksi, and a distal portion having a flexural modulus of less than about30 ksi, wherein the intermediate portion is disposed between theproximal portion and the distal portion.
 6. The catheter shaft accordingto claim 5, further comprising an inner polytetrafluoroethylene tubularmember disposed within the polyoxymethylene-polyurethane elongate shaft.7. The catheter shaft according to claim 6, further comprising a braidedmetallic support member disposed between the innerpolytetrafluoroethylene tubular member and thepolyoxymethylene-polyurethane elongate shaft.
 8. The catheter shaftaccording to claim 6, wherein the proximal portion, intermediate portionand distal portion define a total shaft length and the proximal portionis about 60 to about 90% of the total length, the intermediate portionis about 15 to about 20% of the total length, and the distal portion isabout 2 to about 7% of the total length.
 9. A catheter comprising: aninner tubular member having a proximal end, a distal end and alongitudinal surface; a support member disposed over a substantialportion of the longitudinal surface, the support member having a distalend terminated proximal of the inner tubular member distal end; and apolyoxymethylene-polyurethane elongate shaft disposed over the innertubular member, the polyoxymethylene-polyurethane elongate shaftincluding a proximal portion having about 80 to about 95 weight %polyoxymethylene and about 5 to about 20 weight % polyurethane, anintermediate portion having about 20 to about 50 weight %polyoxymethylene and about 50 to about 80 weight % polyurethane, and adistal portion having about 5 to about 20 weight % polyoxymethylene andabout 80 to about 95 weight % polyurethane, wherein the intermediateportion is disposed between the proximal portion and the distal portion.10. The catheter according to claim 9, wherein the inner tubular membercomprises polytetrafluoroethylene.
 11. The catheter according to claim9, wherein the support member comprises a braided metallic member. 12.The catheter according to claim 9, wherein a manifold is disposed at theproximal end of the inner tubular member.
 13. The catheter according toclaim 9, wherein the proximal portion, intermediate portion and distalportion define a total shaft length and the proximal portion is about 60to about 90% of the total length, the intermediate portion is about 15to about 20% of the total length, and the distal portion is about 2 toabout 7% of the total length.
 14. A balloon catheter comprising: aninner tubular member having a proximal end, a distal end and alongitudinal surface; a support member disposed over a substantialportion of the longitudinal surface, the support member having a distalend terminated proximal of the inner tubular member distal end; apolyoxymethylene-polyurethane elongate shaft including a proximalportion having about 80 to about 95 weight % polyoxymethylene and about5 to about 20 weight % polyurethane, an intermediate portion havingabout 20 to about 50 weight % polyoxymethylene and about 50 to about 80weight % polyurethane, and a distal portion having about 5 to about 20weight % polyoxymethylene and about 80 to about 95 weight %polyurethane, wherein the intermediate portion is disposed between theproximal portion and the distal portion; and a balloon disposed aboutthe distal portion of the polyoxymethylene-polyurethane elongate shaft.15. The balloon catheter according to claim 14, wherein the innertubular member comprises polytetrafluoroethylene.
 16. The ballooncatheter according to claim 14, wherein the support member comprises abraided metallic member.
 17. The balloon catheter according to claim 14,further comprising a manifold disposed at the proximal end of the innertubular member.
 18. The balloon catheter according to claim 14, whereinthe inner tubular member defines a guidewire lumen and an inflationlumen is defined between the inner tubular member and thepolyoxymethylene-polyurethane elongate shaft.
 19. The balloon catheteraccording to claim 14, wherein the proximal portion, intermediateportion and distal portion define a total shaft length and the proximalportion is about 60 to about 90% of the total length, the intermediateportion is about 15 to about 20% of the total length, and the distalportion is about 2 to about 7% of the total length.